1. Field of the Invention
This invention relates to a system and method for providing and displaying map information, including a perspective map, on a portable map display, and in particular a head-worn display.
2. Description of the Related Art
Although the past twenty years has seen rapid advances in the art of global positioning and dynamic map generation, a user that is navigating an unknown city on foot is still burdened with many problems. For instance, traditional paper maps, which are still the dominant navigational tool for walking tourists, are inconvenient to carry and awkward to repeatedly fold and unfold. Furthermore, the user must first locate his or her position on the map, a task that is not always simple, in order to successfully navigate to another location. There is also the problem of the printed map being up-to-date, and showing the information that is relevant to the particular user viewing the map. In addition, the user may want additional information, which can only be provided by another source, such as a guidebook.
One solution to this problem is to use a Global Positioning System (GPS) locator in conjunction with a paper map in order to discover one""s exact location on the map. However, this solution just adds an additional piece of technology to carry, operate, and use in conjunction with an unfolded map.
Another solution to the traditional map problem is to combine Global Positioning System (GPS) technology with digital display technology in order to present the user with a display of a local map with the user""s location indicated in the display. Examples of this combination include the GPS systems in some boats and new cars as well as the new portable GPS receiver/displays. Some of these devices display an electronic image of a map, usually an aerial view, with the user""s position indicated by an icon superimposed on the map image.
These electronic maps do solve the problem of showing both the user""s current location and a map of the surrounding environment, but they have their own problems. First, obviously, the GPS systems embedded in some cars is of no use to a walking tourist. The walking tourist must use some sort of portable (i.e., capable of being carried) device that will not hamper his or her movements. Second, when using such a portable device, there is the problem of the scale and resolution of the map image. On a hand-held device, e.g., a Personal Digital Assistant (PDA) or a Global Positioning System (GPS) receiver/display, the display screen often has low resolution and the displayed map often has a large scale. Both of these factors lead to the user being unable to directly relate the displayed information with the objects and sights around him or her. However, because of the limitations of a hand-held device, this problem is difficult to resolve. If the resolution of the small display screen is increased, the user will be unable to see the details because of the small size of the screen. If the size of the screen is increased, the size of the hand-held instrument will become larger, and, thus, more difficult to carry.
Furthermore, when hand-held devices are used, it is somewhat disruptive of the walking and/or walking tourist experience. For example, to be constantly removing a PDA from one""s pocket or bag in order to reassure oneself of one""s relative location interrupts the flow of a walking tour. This, and the constant focus on a small map in one""s hands, takes away from the ambience, the sights and sounds, of the walking experience. Further still, let us assume the user""s PDA, which displays local maps with GPS information, also has a database of information concerning local sites and eating establishments. If the user wants to access this further information, the user most navigate through the information screens of the PDA, further removing the user from the appreciation of the surrounding environment.
An example of a distracting map device is shown in U.S. Pat. No. 6,016,606 to Oliver et al. This viewing device looks like a short and squat telescope, where the user peers in one end at a map slide continued within, lit up by light entering the lens on the other side. Thus, its lighting operation is similar to a kaleidoscope. The GPS calculated location of the user is superimposed on the map slide. However, continually lifting this device up to the sunlight in order to determine one""s location, or to determine the location of nearby sites, would be a hindrance. Particularly if one could not find an adequate light source. Furthermore, this device provides no information concerning local sites, eating establishments, etc.
Therefore, the need exists for a portable map viewing device, capable of indicating the current location of the user, where the scale and resolution of the map image clearly depict the user""s spatial relationship with the objects shown in the map image. Further, there is a need for such a portable map viewing device which is also capable of showing information concerning the surrounding environment. Further still, there is a need for such a map viewing device, which also does not interfere with the walking, or walking tourist, experience.
An object of the present invention is to provide a system and method for a portable map display device that is capable of indicating the current location of the user.
Another object of the present invention is to provide a system and method for a portable map display device where the scale and resolution of the displayed map image clearly depict the user""s spatial relationship with the objects shown in the displayed map image.
Another object of the present invention is to provide a system and method for a portable map display device which is capable of showing additional non-map information concerning the surrounding environment.
Another object of the present invention is to provide a system and method for a portable map display device which does not interfere with the walking, or walking tourist, experience.
Yet another object of the present invention is to provide a system and method for a portable map display device that displays a perspective map which changes as the user approaches an input destination.
These and other objects are accomplished by the system and method according to the present invention. In one aspect, the system according to the present invention has a portable map display device that has a display unit, a self-locator unit for determining the location of the portable map display device, and a direction detector unit for determining a direction the portable map display device is facing. Map data concerning the area in the vicinity of the determined location in the determined direction is retrieved and sent to a receiver unit in the portable map display device. A data processor in the portable map display device processes the received map data in order that the display unit presents a three dimensional image of the portable map display device vicinity with spatial perspective from the detected direction the portable map display device is facing.
In another aspect, a portable map display system also has a spatial perspective component controller unit for changing at least one component of the viewpoint of the spatial perspective. Components of the viewpoint include a distance d and a view-angle, where the spatial perspective is a projected view from the viewpoint onto a map plane, and the distance d is from the viewpoint to the map plane and the view-angle is formed by the intersection of the map plane with a plane of the viewpoint.
In yet another aspect, the method according to the present invention dynamically produces a three dimensional map image in a portable map display device. In such a method, the location of the portable map display device and the direction the portable map display device is facing is determined. The portable map display device receives map data concerning the area in the vicinity of the determined location in the determined direction of the portable map display device. This received map data is displayed as a three dimensional image of the vicinity of the portable map display device with spatial perspective from the determined direction that the portable map display device is facing.
In still another aspect, the method according to the present invention has the additional steps of inputting a destination, determining a distance from the destination to the portable map display device, and changing the distance d and/or the view-angle of the spatial perspective of the three dimensional image displayed in the portable map display device. The change is proportionate to a change in the determined destination distance.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.